Cable assemblies in industrial robots for transmission of electricity to motors and control systems normally extend through cavities inside the robot. This provides protection against mechanical damage while at the same time the operability of the robot in narrow spaces is improved. The electric power supply and the connection of the robot to a control system are arranged via a cable body connected to the stationary foot of the robot. From here, mounted bundles of insulated conductors branch off and are connected via joints and connectors to the different motor units of the robot. The possibility of inspection and repair of these bundles of insulated conductors extending in narrow channels is limited and such work often entails lengthy shutdowns. Cable assemblies of this kind are shown in GB-A-2 134 074.
The demand for tightness against penetrating liquids, for example water, cutting fluids and hydraulic oil, means that the connectors have to be tight, or that non-tight connectors have to be enclosed in tight spaces. Also branch points and cable joints have to be protected against penetrating liquids, and hence these are often placed in tight enclosures inside the robot. The handling of casings and covers and the inspection of tightness demand a great deal of work and the design is costly. The plurality of joints and connectors also constitutes potential sources of error. The designation "watertight" in the following refers also to tightness against other liquid media such as cutting fluids, hydraulic oil, etc.